In recent years, a new display apparatus having a thin and planar display panel using liquid crystals, electroluminescence, charged fine particles and the like has been widely used instead of the conventional cathode-ray tube. A liquid crystal display apparatus representative of the new display apparatus has not only thin and lightweight properties but also low power consumption and low voltage driving characteristics. The liquid crystal display apparatus has the liquid crystals that are sealed between two substrates. One substrate is an array substrate having a display area in which a plurality of pixels is arranged in a matrix shape, and the other substrate is an opposite substrate that is formed with a color filter, a black matrix (light shield film) and the like. The array substrate and the opposite substrate are bonded with a seal material.
Specifically, since a thin film transistor (TFT) type liquid crystal display apparatus has TFTs, which are switching elements, in respective pixels on the array substrate, the respective pixels can have voltages independently driving the liquid crystals, and thus it is possible to display a high-quality image with less crosstalk. Also, each pixel is provided with a gate wiring (scanning wiring) that controls on-off operations of the TFT and a source wiring (signal wiring), which intersecting with the gate wiring, to input image data. Typically, each pixel corresponds to an area that is surrounded by the gate wirings and the source wirings.
In an in-plane switching (IPS) type (horizontal electric-field type) liquid crystal display apparatus, a plurality of pixel electrodes and opposite electrodes (common electrodes) are arranged alternately at an interval in a slit shape or pectinate shape, as viewed from a plan view, on the same layer or different layer on one array substrate. A generally horizontal electric-field is applied to a substrate surface, and thus an image is displayed. The IPS type has an improved viewing angle characteristic, compared to the conventional TN (Twisted Nematic) type. However, the IPS type has a lower light transmissivity, compared to the TN type, because the electrode parts of the pixel electrodes and opposite electrodes do not mostly contribute to the display.
It is known that an improved horizontal electric-field type apparatus, such as a fringe field switching (FFS) type (for example, JP-A-2009-265484 and JP-A-2010-049185. In a broader interpretation, it is described that the FFS type is also the IPS type). In the FFS type liquid crystal display apparatus, the pixel electrodes and the opposite electrodes are formed on one array substrate, like the IPS type. However, the pixel electrodes and the opposite electrodes are arranged with being overlapped vertically with sandwiching an insulation film therebetween. Also, generally, the lower electrode has a plate (plane) shape and the upper electrode has a slit shape or pectinate shape having an opening.
In the FFS type, the pixel electrode is any one of the lower electrode and the upper electrode. In the FFS type, since the liquid crystals are driven by the fringe electric-field between the upper and lower electrodes, the liquid crystals above the electrode parts of the upper electrodes are also driven to contribute to the display. Thereby, the light transmissivity is improved, compared to the IPS type.